[PATCH 6/7] ASoC: mediatek: mt8188: add bus protection

[Trevor Wu <trevor.wu@xxxxxxxxxxxx>]

Add bus protection for reset controller.

Signed-off-by: Trevor Wu <trevor.wu@xxxxxxxxxxxx>
---
 sound/soc/mediatek/mt8188/mt8188-afe-pcm.c | 76 ++++++++++++++++++++++
 1 file changed, 76 insertions(+)

diff --git a/sound/soc/mediatek/mt8188/mt8188-afe-pcm.c b/sound/soc/mediatek/mt8188/mt8188-afe-pcm.c
index fecc891f892d..c3fd32764da0 100644
--- a/sound/soc/mediatek/mt8188/mt8188-afe-pcm.c
+++ b/sound/soc/mediatek/mt8188/mt8188-afe-pcm.c
@@ -17,6 +17,7 @@
 #include <linux/of_address.h>
 #include <linux/of_platform.h>
 #include <linux/pm_runtime.h>
+#include <linux/soc/mediatek/infracfg.h>
 #include <linux/reset.h>
 #include <sound/pcm_params.h>
 #include "mt8188-afe-common.h"
@@ -3133,12 +3134,68 @@ static int mt8188_afe_parse_of(struct mtk_base_afe *afe,
 	return 0;
 }
 
+#define MT8188_DELAY_US 10
+#define MT8188_TIMEOUT_US USEC_PER_SEC
+
+static int bus_protect_enable(struct regmap *regmap)
+{
+	int ret;
+	u32 val;
+	u32 mask;
+
+	val = 0;
+	mask = MT8188_TOP_AXI_PROT_EN_2_AUDIO_STEP1;
+	regmap_write(regmap, MT8188_TOP_AXI_PROT_EN_2_SET, mask);
+
+	ret = regmap_read_poll_timeout(regmap, MT8188_TOP_AXI_PROT_EN_2_STA,
+				       val, (val & mask) == mask,
+				       MT8188_DELAY_US, MT8188_TIMEOUT_US);
+	if (ret)
+		return ret;
+
+	val = 0;
+	mask = MT8188_TOP_AXI_PROT_EN_2_AUDIO_STEP2;
+	regmap_write(regmap, MT8188_TOP_AXI_PROT_EN_2_SET, mask);
+
+	ret = regmap_read_poll_timeout(regmap, MT8188_TOP_AXI_PROT_EN_2_STA,
+				       val, (val & mask) == mask,
+				       MT8188_DELAY_US, MT8188_TIMEOUT_US);
+	return ret;
+}
+
+static int bus_protect_disable(struct regmap *regmap)
+{
+	int ret;
+	u32 val;
+	u32 mask;
+
+	val = 0;
+	mask = MT8188_TOP_AXI_PROT_EN_2_AUDIO_STEP2;
+	regmap_write(regmap, MT8188_TOP_AXI_PROT_EN_2_CLR, mask);
+
+	ret = regmap_read_poll_timeout(regmap, MT8188_TOP_AXI_PROT_EN_2_STA,
+				       val, !(val & mask),
+				       MT8188_DELAY_US, MT8188_TIMEOUT_US);
+	if (ret)
+		return ret;
+
+	val = 0;
+	mask = MT8188_TOP_AXI_PROT_EN_2_AUDIO_STEP1;
+	regmap_write(regmap, MT8188_TOP_AXI_PROT_EN_2_CLR, mask);
+
+	ret = regmap_read_poll_timeout(regmap, MT8188_TOP_AXI_PROT_EN_2_STA,
+				       val, !(val & mask),
+				       MT8188_DELAY_US, MT8188_TIMEOUT_US);
+	return ret;
+}
+
 static int mt8188_afe_pcm_dev_probe(struct platform_device *pdev)
 {
 	struct mtk_base_afe *afe;
 	struct mt8188_afe_private *afe_priv;
 	struct device *dev;
 	struct reset_control *rstc;
+	struct regmap *infra_ao;
 	int i, irq_id, ret;
 
 	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(33));
@@ -3163,18 +3220,37 @@ static int mt8188_afe_pcm_dev_probe(struct platform_device *pdev)
 		return dev_err_probe(dev, PTR_ERR(afe->base_addr),
 				     "AFE base_addr not found\n");
 
+	infra_ao = syscon_regmap_lookup_by_phandle(dev->of_node,
+						   "mediatek,infracfg");
+	if (IS_ERR(infra_ao))
+		return dev_err_probe(dev, PTR_ERR(infra_ao),
+				     "%s() Cannot find infra_ao controller\n",
+				     __func__);
+
 	/* reset controller to reset audio regs before regmap cache */
 	rstc = devm_reset_control_get_exclusive(dev, "audiosys");
 	if (IS_ERR(rstc))
 		return dev_err_probe(dev, PTR_ERR(rstc),
 				     "could not get audiosys reset\n");
 
+	ret = bus_protect_enable(infra_ao);
+	if (ret) {
+		dev_err(dev, "bus_protect_enable failed\n");
+		return ret;
+	}
+
 	ret = reset_control_reset(rstc);
 	if (ret) {
 		dev_err(dev, "failed to trigger audio reset:%d\n", ret);
 		return ret;
 	}
 
+	ret = bus_protect_disable(infra_ao);
+	if (ret) {
+		dev_err(dev, "bus_protect_disable failed\n");
+		return ret;
+	}
+
 	/* initial audio related clock */
 	ret = mt8188_afe_init_clock(afe);
 	if (ret)
-- 
2.18.0